The present invention relates to hand wrenches, such as for tightening or loosening fasteners.
Numerous wrenches are known in the art. For example, a conventional box end wrench typically has two faceted openings, one on each end, for receiving a faceted fastener, such as a conventional hexagonal nut. Such box end wrenches typically require that the wrench be repositioned numerous times to rotate the nut to the desired position, which is cumbersome. As such, ratcheting box end wrenches have been developed that allow for easier use. However, even ratcheting box end wrenches are designed for a specific size, or a very limited range of sizes, of nuts. Therefore, multiple ratcheting box end wrenches are required for jobs with multiple sizes of nuts. And, conventional ratcheting box end wrenches may be unsuited to some types of fasteners, such as TORX brand fasteners.
Other known wrenches include relatively pivoting handles and provide for the nut to be gripped by moving multiple jaw elements inward in response to closing together of the handles. For example, U.S. Pat. No. 2,787,925 shows such a wrench, sometimes referred to as a grip wrench. However, the Buchannan tool requires that the user manually hold the handles together against spreading when applying torque to the nut. As such, the torque applied to the fastener by the Buchannan tool may be limited by the user's grip strength, which may be insufficient in some situations.
Thus, while the prior art wrenches may be suitable for some situations, they may not be suitable for all situations. Accordingly, there remains a need for alternative wrenches, particularly variable-size wrenches that provide secure gripping.